A small-size, portable music player that has a flash memory or other relatively small-sized memory and plays song data stored in the memory is now commercially available. The user of the music player connects the music player to a PC and downloads song data from the PC to the music player.
A music data download system disclosed by Patent Document 1 (Japanese Patent Laid-open No. 2002-108747) downloads song data, to which playback control information is added, from a server to a terminal. The terminal exercises song data playback control in accordance with the playback control information.
Further, the invention disclosed by Patent Document 2 (Japanese Patent Laid-open No. Hei 10-208445) furnishes an administration section, for instance, of a radio station with a shelf for storing media on which music data is recorded, playback means for playing back the music data from the media, and retention means for retaining the music data in such a manner as to transfer the music data at a high speed to a studio or other terminal section via a network. The shelf is used to store media on which infrequently used music data is recorded. The retention means is used to retain frequently used music data. In accordance with the frequency of music data use, this invention uses the shelf, playback means, or retention means to store or retain the media or music data.
However, the aforementioned small-size, portable music player having a flash memory or other relatively small-sized memory cannot retain hundreds or thousands of songs. Therefore, the user of the small-size, portable music player has to marshal song data as needed within the music player before downloading new song data or the song data deleted from the music player from a PC to the music player.
However, the user finds it troublesome to select the songs to be deleted from the music player or may be at a loss what songs to delete. The user also finds it troublesome to select the songs to be transferred from the PC to the music player. The greater the number of songs stored on the PC, the more often the user is at a loss what songs to transfer.
The present invention has been made to provide a natural method for replacing songs stored in the music player by the other songs stored in the server in accordance with the user's estimated preferences and wishes and without requiring the user to perform a special procedure, exercise judgment, or become conscious of individual songs.